The present invention generally relates to an improved cracking die assembly for use in a high production nutcracking apparatus.
In prior U.S. Pat. No. 3,871,275, there is disclosed a high production nutcracking apparatus wherein a plurality of cracking units are arranged on a rotatable turret, with each cracking unit having an opening adapted to receive an individual nut which is dropped from a feed conveyor as the cracking unit moves through its top center position. Each cracking unit includes an anvil mounted on one side of the opening, and a cracking die mounted for limited movement on the other side of the opening and so that the anvil and cracking die are adapted to receive and hold the nut therebetween. A free floating shuttle is mounted rearwardly of the die, and the shuttle is thrust forwardly into impacting engagement with the rearward side of the cracking die after the nut is received in the opening, and so that the shell of the retained nut will be cracked by the resulting forward movement of the die.
Prior U.S. Pat. Nos. 4,332,827 and 5,623,867, disclose improved high production nutcracking apparatus, which includes an improved nut feeding conveyor by which the nuts are singularized and oriented prior to being delivered to the individual cracking units.
Prior U.S. Pat. Nos. 4,441,414 and 6,182,562 disclose a cracking die assembly for a high speed nutcracking apparatus of the type disclosed in the above patents and which comprises a retainer mounted within the bore of a mounting sleeve. The cracking die has a radial flange mounted to oppose a shoulder in the bore of the retainer so as to permit limited movement in the axial direction, and an annular resilient gasket is disposed between the flange of the die and the retainer shoulder and so as to absorb at least a portion of the impacting force from the shuttle.
During high speed operation, the annular gaskets are subjected to repeated impacts and to heat generated from the friction resulting from the relative axial movement between the gasket and the retainer, and between the gasket and the die. As a result, the gasket rapidly deteriorates in use, requiring repeated disassembly of the cracking die assembly.
It is accordingly an object of the present invention to provide a cracking die assembly adapted for use in a high speed nutcracking apparatus of the described type, and which minimizes the deterioration of the gasket in use, to thereby minimize the frequency of the replacement of the gasket.
The above and other objects and advantages of the present invention are achieved by the provision of a cracking die assembly which comprises a tubular retainer having an internal bore which includes a forwardly facing shoulder and a rearwardly facing shoulder, so that the two shoulders face each other in a spaced apart arrangement which defines a cylindrical cavity therebetween having a predetermined diameter. An annular gasket is mounted within the cylindrical cavity, and the gasket has an axial dimension which is approximately the same as the distance between the shoulders so as to be retained therebetween. The gasket has an outer diameter which is less than the predetermined diameter of the cylindrical cavity so as to define a space therebetween, which allows the gasket to radially expand upon being impacted by the crack die during operation of the cracking apparatus.
Thus with the present invention, the gasket absorbs and dissipates at least a portion of the energy imparted by the impact of the shuttle, through a radial expansion of the gasket, rather than by an internal compression of the gasket. The repeated internal compression of the gasket as occurs with the prior art designs is believed to contribute to the heating and thus the deterioration of the gasket, and such effects can be minimized with the present invention.
In one embodiment of the invention, the opposing surfaces of the gasket and cracking die are generally perpendicular to a central axis defined by the retainer. In another embodiment, the opposing surfaced comprise mating conical surfaces which are inclined at an angle of inclination of between about 30xc2x0 C. and 60xc2x0.
Since the annular gasket is of substantially the same axial extent as the distance between the opposing shoulders of the retainer, it is essentially locked against axial movement in the retainer, so as to eliminate the heat generated by the friction associated with its axial movement. Also, the gasket includes a flexible sealing lip which engages the die so as to further reduce friction and also prevent the inflow of air and debris into the interior of the retainer.